This invention relates generally to database query optimization, and more generally to optimization of queries for databases having compressed data.
In order to conserve resources and processing time, many databases are compressed at the storage level using, for example, run-length encoding (RLE) compression or other compression techniques. Compression conserves storage space and reduces the number of read requests. However, queries conventionally decompress compressed stored data and operate on uncompressed data. Thus, in order to execute a query on compressed databases, the data must be first decompressed and the query executed multiple times on decompressed data that may be the same. The multiple intermediate results must then be aggregated to obtain an answer. This is inefficient, and results in substantial and costly processing and long overall response times.
It is desirable to provide systems and methods that address these and other known problems of executing queries on compressed data by minimizing computation costs and reducing query response time, and it is to these ends that the invention is directed.